2 September 2012 Last updated at 07:39 ET

Lia Green death: Three-year-old suffered 'severe internal injuries'

Lia Green was taken to hospital from her home in Preston

A child who died on her way to hospital had suffered "severe internal injuries caused by violence", police have said.

Three-year-old Lia Green was pronounced dead on arrival at Royal Preston Hospital after paramedics were called to her Norris Street home on Thursday.

A Lancashire Police spokesman said the investigation into her death was centring around her family.

A 22-year-old man and a 20-year-old woman who were arrested on suspicion of murder remain in police custody.

The spokesman said a post-mortem examination had revealed the injuries to the child.

He said officers were investigating the events in the days leading up to her death and that the three-year-old's family were a "key part" of that investigation.

He added that the murder inquiry was a major operation for the force and over 30 officers were working on it.